You have to luv these cars....' 92 convert.
speed control just kicked out and now wont work....ideas

 

Not sure if you have a 6 or a 12 or if it even makes a difference.

For my car MY94 4.0L I would check the following to start with.

Check fuse on front left fender
Switch in the dash, pop it out and check cleanliness and security of connections.
Cruise control module in front of passenger seat, check connections and test the I/O
Check the mechanical linkage to the throttle
Check vacuum control pump and vacuum lines.

If you download the electrical guide from the "how to"section at the top of this forum it will be very helpful to you.

Cheers,

Allan

 

Also check that the bellows on the actuator is sealing properly around the edges.

 

If the bellows type the control unit can fail due to ageing capacitors. You can try adjusting with the two tiny potentiometers inside, one for coarse and one for fine adjustment. If it doesnt engage at all also check connections at the vac solenoids. And of course the vac hosrs themselves. If later six with stepper motor start by checking connections.

 

Thanks all. 1992 v12. Checked the 3 amp fuse in the car, ok. couldn't find a fuse for it under the hood.... l will check the switch at the weekend. Gotta read up about all those vacuum things. lol

 

I'd look at the vacuum pump and dump valve, with external 12V source to see if those electrical components are functional. The dump valve is mounted on the inner wing behind the vacuum pump (look for the mesh grill on the end).